Heretofore, there has been used an apparatus that can read by means of a magnetic sensor, an identification pattern like a diagram or a character being printed on printed matter, for example, a bill, a check, and the like whereby whether the document is genuine or spurious is discriminated or further various sorts of documents such as the denominations of currency are identified.
In the past, apparatus of this type has had magnetic sensor disposed in the interior of the passage wherethrough printed matter was fed in, and thereby compared a pattern signal with a standard signal, both being detected with a reference position being set, for example on the front edge of the printed matter, in a one and only position where their respective reference positions were made to coincide each with other, as a consequence of which there occurred a moot point that a discrepancy arose between the pattern signal of the magnetic sensor and the standard signal thereof resulting from the expansion and contraction of the above-mentioned printed matter, or from the shearing in printing thereof, or from the till of the printed matter within the feeding passage, all of these phenomena being attributable, for example, to the wearing-out by use of the printed matter or further to shrivelling thereof, with the result that the identification precision was lowered. By the way, in particular for the dollar bills of America where the worn-out bills are never withdrawn from circulation in order, such mooted point is revealed more markably.